Insufflation system and insufflation apparatus

ABSTRACT

There is provided an insufflation system and an insufflation apparatus which can prevent a pressure inside a lumen from rapidly increasing and can achieve operability matched to a sense of an operator. When the operator operates an air/water supply button of the endoscope, the gas is insufflated into a gastrointestinal tract of a patient through an internal conduit of the endoscope (manual insufflation). Meanwhile, the insufflation apparatus is connected to an insertion assisting tool which guides the endoscope into the gastrointestinal tract. When the insufflation apparatus automatically performs insufflation, the gas is intermittently insufflated into the gastrointestinal tract of the patient so as to maintain the pressure inside the gastrointestinal tract at the set pressure (automatic insufflation). The average flow rate of the gas in the automatic insufflation is set to be less than or equal to the insufflation flow rate in the manual insufflation.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. §119 to JapanesePatent Application No. 2014-080256, filed on Apr. 9, 2014. The aboveapplication is hereby expressly incorporated by reference, in itsentirety, into the present application.

TECHNICAL FIELD

The present disclosure relates to an insufflation system, and moreparticularly to an insufflation system and an insufflation apparatuswhich enables manual insufflation and automatic insufflation into alumen of a living body.

DESCRIPTION OF THE BACKGROUND ART

Conventionally, when inspections and treatments are performed using anendoscope, air is insufflated into the lumen through an insufflationconduit provided in the endoscope to secure a field of view of theendoscope and secure an operational area of treatment tools. Air hasbeen mainly used as the gas to be insufflated into the lumen in aconventional art, but carbon dioxide gas (CO₂ gas) has been used inrecent years. Since carbon dioxide gas has favorable bioabsorbability,there is little damage to the subject. For this reason, there is atendency for carbon dioxide gas to be used as a gas supply source.

The insufflation system which insufflates gas into the lumen has anadvantage in that when carbon dioxide gas is manually insufflated intothe lumen according to the operation by an operator, the operator canfreely adjust an amount of gas to be insufflated into the lumenaccording to the intention of the operator, but has a disadvantage inthat the operator needs to perform frequent operations in order to keepthe pressure inside the lumen constant, thereby increasing anoperational burden of the operator.

In view of this, there has been proposed an insufflation system having afunction to automatically insufflate carbon dioxide gas into the lumento maintain the pressure inside the lumen at a constant pressure (forexample, see Japanese Patent Application Laid-Open No. 2012-200530 andNo. H05-329098). The insufflation systems can control the pressureinside the lumen to be stably maintained in a desired state withoutrequiring the operator to perform complicated operations, and hence canreduce the operational burden of the operator.

SUMMARY

By the way, there has been a need to develop an insufflation systemwhich enables manual insufflation and automatic insufflation. Theinsufflation system can manually insufflate air into the lumen accordingto the operation by the operator while automatically insufflating air sothat the pressure inside the lumen becomes a predetermined pressure,thereby allowing the operational burden of the operator to be reducedand allowing the pressure inside the lumen to be finely adjustedaccording to the intention of the operator, and thus improvingconvenience.

However, if the flow rate of automatic insufflation (volume of gasinsufflated per unit time) is not set to an appropriate amount in theabove insufflation system, the pressure inside the lumen is rapidlyincreased during automatic insufflation, thus causing a problem ofincreasing the burden on a patient.

From the point of view of operability, it is desirable for the operatorto perform automatic insufflation into the lumen with a sense as closelysimilar to manual insufflation as possible.

Particularly when air is insufflated into a lumen such as the stomachand large intestine, finer operations may be required in comparison withthe operation when air is insufflated into a body cavity such as theabdomen. Therefore, even if manual insufflation and automaticinsufflation are used concurrently, the operability matched to the senseof the operator is highly required.

Japanese Patent Application Laid-Open No. 2012-200530 and No. H05-329098disclose the insufflation system having a function to automaticallyinsufflate carbon dioxide gas into the lumen so that the pressure insidethe lumen becomes a predetermined pressure, but do not pay attention tothe aforementioned problems, nor do they mention any device for solvingthe problems.

In view of the above circumstances, the present disclosure has beenmade, and the present disclosure provides an insufflation system and aninsufflation apparatus which enables manual insufflation and automaticinsufflation into a lumen of a living body, and more particularly to aninsufflation system and an insufflation apparatus which can prevent thepressure inside the lumen from rapidly increasing and can achieveoperability suited to a sense of the operator.

In order to solve the above problems, an insufflation system accordingto one aspect of the present disclosure, which insufflates a gassupplied from a gas supply source into a lumen of a living body,comprising: a first insufflation conduit through which the gas isautomatically insufflated into the lumen; a second insufflation conduitthrough which the gas is insufflated into the lumen in response tomanual operation; a pressure detecting device configured to detect apressure inside the lumen; and a control device configured to control aninsufflation flow rate of the gas insufflated through the firstinsufflation conduit, based on a pressure difference between thepressure detected by the pressure detecting device and a preset setpressure, the control device configured to alternately repeat aninsufflation step of insufflating the gas through the first insufflationconduit and a pressure detection step of stopping insufflating the gasand detecting the pressure inside the lumen by the pressure detectingdevice, wherein when one cycle is defined as one repeating unit formedof the insufflation step and the pressure detection step, an averageflow rate per cycle is set to be less than or equal to the insufflationflow rate when the gas is insufflated through the second insufflationconduit.

According to the first aspect, the automatic insufflation into the lumenis intermittently performed and the average flow rate per cycle is setto be less than or equal to the insufflation flow rate of the manualinsufflation, which allows the automatic insufflation into the lumen tobe performed with a sense as close to the manual insufflation. Thismakes it possible to prevent the pressure inside the lumen from rapidlyincreasing and to achieve operability matched to a sense of theoperator.

In the insufflation system according to the aspect of the presentdisclosure, it is preferable that, when the pressure difference betweenthe pressure detected by the pressure detecting device and the setpressure is less than or equal to a threshold, the control device setsan insufflation time per cycle of the gas insufflated through the firstinsufflation conduit such that the greater the pressure difference, thelonger the insufflation time per cycle, and when the pressure differenceexceeds the threshold, the control device sets the insufflation time percycle of the gas insufflated through the first insufflation conduit to apredetermined time regardless of the pressure difference, and theaverage flow rate when the insufflation time per cycle is set to thepredetermined time is set to be less than or equal to the insufflationflow rate when the gas is insufflated through the second insufflationconduit.

According to the aspect, the insufflation time per cycle in theautomatic insufflation is set according to the pressure differencebetween the pressure inside the lumen and the set pressure, which canstabilize the automatic insufflation into the lumen.

In addition, the average flow rate when the insufflation time per cyclein the automatic insufflation is set to the predetermined time is set tobe less than or equal to the insufflation flow rate of the manualinsufflation, and hence the automatic insufflation into the lumen can beperformed with a sense close to the manual insufflation. This makes itpossible to prevent the pressure inside the lumen from rapidlyincreasing and to achieve operability matched to a sense of theoperator.

An insufflation system according to another aspect of the presentdisclosure, which insufflates a gas supplied from a gas supply sourceinto a lumen of a living body, comprising: a first insufflation conduitthrough which the gas is automatically insufflated into the lumen; asecond insufflation conduit through which the gas is insufflated intothe lumen in response to manual operation; a pressure detecting deviceconfigured to detect a pressure inside the lumen; a control deviceconfigured to control an insufflation flow rate of the gas insufflatedthrough the first insufflation conduit, based on a pressure differencebetween the pressure detected by the pressure detecting device and apreset set pressure, the control device configured to alternately repeatan insufflation step of insufflating the gas through the firstinsufflation conduit and a pressure detection step of stoppinginsufflating the gas and detecting the pressure inside the lumen by thepressure detecting device; a first flow rate restricting deviceconfigured to restrict the insufflation flow rate of the gas insufflatedthrough the first insufflation conduit; and a second flow raterestricting device configured to restrict the insufflation flow rate ofthe gas insufflated through the second insufflation conduit, whereinwhen one cycle is defined as one repeating unit formed of theinsufflation step and the pressure detection step, a restricted amountof the insufflation flow rate of the gas by the first flow raterestricting device and the second flow rate restricting device is setaccording to a duty ratio of an insufflation time per cycle of the gasinsufflated through the first insufflation conduit.

According to the aspect, the automatic insufflation into the lumen isintermittently performed, and the restricted amount of the insufflationflow rate of the gas by the first flow rate restricting device and thesecond flow rate restricting device is set according to the duty ratioof the insufflation time per cycle in the automatic insufflation. Thus,the automatic insufflation into the lumen can be performed with a senseclose to the manual insufflation. This makes it possible to prevent thepressure inside the lumen from rapidly increasing and to achieveoperability matched to a sense of the operator.

In the insufflation system according to the another aspect of thepresent disclosure, it is preferable that the first flow raterestricting device includes a first orifice, and the second flow raterestricting device includes a second orifice, wherein when the dutyratio of the insufflation time per cycle of the gas insufflated throughthe first insufflation conduit is less than or equal to D, a ratio of aneffective opening area of the first orifice to an effective opening areaof the second orifice is configured to be less than or equal to 1/Dtimes.

According to the aspect, assuming that the duty ratio of theinsufflation time per cycle in the automatic insufflation is less thanor equal to D, the ratio of the effective opening area of the firstorifice to the effective opening area of the second orifice isconfigured to be less than or equal to 1/D times, and hence theautomatic insufflation into the lumen can be performed with a senseclose to the manual insufflation. This makes it possible to prevent thepressure inside the lumen from rapidly increasing and to achieveoperability matched to a sense of the operator.

In the aspect, it is more preferable that the duty ratio of theinsufflation time per cycle of the gas insufflated through the firstinsufflation conduit is configured to be less than or equal to 0.7, andthe effective opening area of the first orifice is configured to be lessthan or equal to 1.43 times the effective opening area of the secondorifice.

According to that aspect, the insufflation flow rate in the automaticinsufflation and the insufflation flow rate of the manual insufflationare set to appropriate amounts, whereby the automatic insufflation intothe lumen can be performed with a sense close to the manualinsufflation. This makes it possible to prevent the pressure inside thelumen from rapidly increasing and to achieve operability matched to asense of the operator.

An insufflation apparatus according to yet another aspect of the presentdisclosure, which insufflates a gas supplied from a gas supply sourceinto a lumen of a living body, comprising: a pressure detecting deviceconfigured to detect a pressure inside the lumen; and a control deviceconfigured to control an insufflation flow rate of the gas supplied to afirst external conduit which is connected to the insufflation apparatusand through which the gas is automatically insufflated into the lumen,based on a pressure difference between the pressure detected by thepressure detecting device and a preset set pressure, the control deviceconfigured to alternately repeat an insufflation step of insufflatingthe gas into the first external conduit and a pressure detection step ofstopping insufflating the gas and detecting the pressure inside thelumen by the pressure detecting device, wherein when one cycle isdefined as one repeating unit formed of the insufflation step and thepressure detection step, an average flow rate per cycle of the gassupplied to the first external conduit is set to be less than or equalto the insufflation flow rate of the gas supplied to a second externalconduit which is connected to the insufflation apparatus and throughwhich the gas is insufflated into the lumen in response to manualoperation.

An insufflation apparatus according to yet further another aspect of thepresent disclosure, which insufflates a gas supplied from a gas supplysource into a lumen of a living body, comprising: a pressure detectingdevice configured to detect a pressure inside the lumen; a controldevice configured to control an insufflation flow rate of the gassupplied to a first external conduit which is connected to theinsufflation apparatus and through which the gas is automaticallyinsufflated into the lumen, based on a pressure difference between thepressure detected by the pressure detecting device and a preset setpressure, the control device configured to alternately repeat aninsufflation step of insufflating the gas into the first externalconduit and a pressure detection step of stopping insufflating the gasand detecting the pressure inside the lumen by the pressure detectingdevice; a first flow rate restricting device configured to restrict theinsufflation flow rate of the gas supplied to the first externalconduit; and a second flow rate restricting device configured torestrict the insufflation flow rate of the gas supplied to a secondexternal conduit which is connected to the insufflation apparatus andthrough which the gas is insufflated into the lumen in response tomanual operation, wherein when one cycle is defined as one repeatingunit formed of the insufflation step and the pressure detection step, arestricted amount of the insufflation flow rate of the gas by the firstflow rate restricting device and the second flow rate restricting deviceis set according to a duty ratio of an insufflation time per cycle ofthe gas supplied to the first external conduit.

The present disclosure can prevent the pressure inside the lumen fromrapidly increasing and achieve operability matched to a sense of theoperator.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an entire configuration diagram illustrating a schematicconfiguration of an insufflation system according to an embodiment ofthe present disclosure.

FIG. 2 is perspective view illustrating a distal end portion of aninsertion portion of an endoscope.

FIG. 3 is a configuration diagram schematically illustrating a conduitconfiguration of the endoscope and an insertion assisting tool.

FIG. 4 is a block diagram illustrating a configuration of aninsufflation apparatus.

FIG. 5 is a diagram illustrating a front panel of the insufflationapparatus.

FIG. 6 is a view illustrating a usage state of the insufflation systemaccording to the present embodiment.

FIG. 7 is an explanatory drawing used to describe an aspect of manualinsufflation.

FIG. 8 is an explanatory drawing used to describe an aspect of automaticinsufflation.

FIG. 9 is an explanatory drawing used to describe an aspect of automaticinsufflation.

FIG. 10 is a graph illustrating a relationship between a pressuredifference and a duty ratio of an insufflation step (time of theinsufflation step).

FIG. 11 is a flowchart illustrating an example of an operation of theinsufflation apparatus.

FIG. 12 is a flowchart illustrating a processing procedure for automaticinsufflation control.

FIG. 13 is a schematic diagram schematically illustrating a conduitconfiguration of an endoscope as a first modification.

FIG. 14 is an entire configuration diagram illustrating a schematicconfiguration of an endoscope system as a second modification.

FIG. 15 is a conduit configuration diagram illustrating an internalconfiguration of the endoscope illustrated in FIG. 14.

FIG. 16 is a schematic diagram schematically illustrating a conduitconfiguration of an endoscope as a third modification.

FIG. 17 is a block diagram illustrating a configuration of aninsufflation apparatus as a third modification.

DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

Hereinafter, a preferable embodiment of the present disclosure will bedescribed in detail with reference to the accompanying drawings.

FIG. 1 is an entire configuration diagram illustrating a schematicconfiguration of an insufflation system according to an embodiment ofthe present disclosure. The insufflation system illustrated in FIG. 1mainly includes an endoscope 10, an insertion assisting tool 70, a lightsource apparatus 20, a processor 30, and an insufflation apparatus 66.

The endoscope 10 includes an insertion portion 12 which is inserted intoa lumen of a patient, for example, a gastrointestinal tract such asstomach and large intestine; and a hand operating unit 14 which iscontinuously connected to the insertion portion 12. A universal cable 16is connected to the hand operating unit 14. An LG (Light Guide)connector 18 is provided at a distal end of the universal cable 16.Illumination light can be transmitted to an illumination optical system54 to be described later (see FIG. 2) by detachably connecting the LGconnector 18 to the light source apparatus 20. An electrical connector24 is connected to the LG connector 18 through a cable 22, and theelectrical connector 24 is detachably connected to the processor 30.Note that a tube 26 for air/water insufflation and a tube 28 for suctionare also connected to the LG connector 18.

The hand operating unit 14 includes an air/water insufflation button 32,a suction button 34, and a shutter button 36, which are arranged side byside, as well as a pair of angle knobs 38 and 38, and a forcepsinsertion portion 40.

Meanwhile, the insertion portion 12 includes a distal end portion 46, acurved portion 48, and a flexible portion 50. The curved portion 48 isremotely bent by rotating the pair of angle knobs 38 and 38 provided inthe hand operating unit 14. This makes it possible to direct a distalend surface 47 of the distal end portion 46 in a desired direction.

As illustrated in FIG. 2, the distal end surface 47 of the distal endportion 46 includes an observation optical system 52, illuminationoptical systems 54 and 54, an air/water insufflation nozzle 56, and aforceps port 58. A CCD (Charge Coupled Device) (unillustrated) isdisposed rearward of the observation optical system 52. A signal cableis connected to a substrate which supports the CCD. The signal cable isinserted into the insertion portion 12, the hand operating unit 14, andthe universal cable 16 in FIG. 1, and extends up to the electricalconnector 24 to be connected to the processor 30. Thus, an observedimage captured by the observation optical system 52 in FIG. 2 is formedon a light receiving surface of the CCD, in which the image is convertedto an electrical signal. The electrical signal is outputted to theprocessor 30 in FIG. 1 through the signal cable, and then converted to avideo signal. Thus, the observed image is displayed on a monitor 60connected to the processor 30.

An exit end of a light guide (unillustrated) is disposed rearward of theillumination optical systems 54 and 54 in FIG. 2. The light guide isinserted into the insertion portion 12, the hand operating unit 14, andthe universal cable 16 in FIG. 1. An incident end of the light guide isdisposed at a light guide rod 19 (see FIG. 3) of the LG connector 18.When the light guide rod 19 of the LG connector 18 is connected to thelight source apparatus 20, illumination light emitted from the lightsource apparatus 20 is transmitted to the illumination optical systems54 and 54 through the light guide, and then the illumination light isemitted from the illumination optical systems 54 and 54.

The insertion assisting tool 70 is used to guide the insertion portion12 of the endoscope 10 into a gastrointestinal tract. The insertionassisting tool 70 is a tubular body having sufficient flexibility andincludes an insertion channel 68 (see FIG. 3) penetrating from theproximal end to the distal end. The inner diameter of the insertionassisting tool 70, that is, the diameter of the insertion channel 68, isslightly larger than the outer diameter of the insertion portion 12, andhence the insertion assisting tool 70 is large enough to insert theinsertion portion 12 thereinto.

When the insertion portion 12 of the endoscope 10 is inserted into thegastrointestinal tract, the insertion portion 12 is inserted into theinsertion channel 68 of the insertion assisting tool 70 so as to bedisposed in a state in which the insertion assisting tool 70 covers theouter peripheral surface of the insertion portion 12.

In addition, the proximal end of the insertion assisting tool 70includes a rigid grip portion 74. The proximal end surface of the gripportion 74 includes an opening for inserting the insertion portion 12 ofthe endoscope 10 into the insertion channel 68 of the insertionassisting tool 70. The outer peripheral surface of the grip portion 74includes a gas supply port 76 for supplying carbon dioxide gas. The gassupply port 76 is connected to the insufflation apparatus 66 through anautomatic insufflation tube 64. Note that the automatic insufflationtube 64 corresponds to a first external conduit.

Here, the description focuses on the conduit configuration of theendoscope 10 and the insertion assisting tool 70.

FIG. 3 is a configuration diagram schematically illustrating the conduitconfiguration of the endoscope 10 and the insertion assisting tool 70.As illustrated in FIG. 3, an air/water insufflation tube 80 is connectedto an air/water insufflation nozzle 56 provided at the distal endsurface 47 of the insertion portion 12. The air/water insufflation tube80 is branched into an insufflation tube 82 and a water insufflationtube 84, each of which is connected to a valve 86 disposed in the handoperating unit 14. An air supply tube 88 and a water supply tube 90 areconnected to the valve 86, to which an air/water insufflation button 32is attached. In a state in which the air/water insufflation button 32 isprojected, the insufflation tube 82 communicates with the air supplytube 88. When the air/water insufflation button 32 is pressed down, thewater insufflation tube 84 communicates with the water supply tube 90.The air/water insufflation button 32 includes a vent (unillustrated),through which the air supply tube 88 communicates with the outside air.

The air supply tube 88 and the water supply tube 90 are inserted intothe universal cable 16, and extend up to a water insufflation connector92 of the LG connector 18. A tube 26 is detachably connected to thewater insufflation connector 92. The distal end of the tube 26 isconnected to a water storage tank 27. The water supply tube 90communicates below a liquid surface of the water storage tank 27, andthe air supply tube 88 communicates above the liquid surface thereof.

An air tube 94 is connected to the water insufflation connector 92. Theair tube 94 communicates with the air supply tube 88. In addition, theLG connector 18 is connected to the light source apparatus 20, therebycommunicating the air tube 94 with an air pump 21 inside the lightsource apparatus 20. Thus, when the air pump 21 is driven to blow air,the air is delivered to the air supply tube 88 through the air tube 94.While the air/water insufflation button 32 is not operated, the airescapes to the outside through the vent (unillustrated). When theoperator closes the vent, the air is passed from the air supply tube 88to the insufflation tube 82 and is jetted from the air/waterinsufflation nozzle 56. When the operator presses down the air/waterinsufflation button 32, the air supply tube 88 is disconnected from theinsufflation tube 82, and then the air fed into the air tube 94 issupplied above the liquid surface of the water storage tank 27. Thisincreases the internal pressure of the water storage tank 27 to causewater to be supplied to the water supply tube 90. Then, the water isdelivered to the water insufflation tube 84 and is jetted from theair/water insufflation nozzle 56. Thus, the observation optical system52 is cleaned by jetting water or air from the air/water insufflationnozzle 56 onto the observation optical system 52.

A forceps tube 96 is connected to the forceps port 58 provided on thedistal end surface 47 of the insertion portion 12. The forceps tube 96is branched into two: one communicating with a forceps insertion portion40 and the other communicating with a valve 98. Thus, when a treatmenttool such as a forceps is inserted from the forceps insertion portion40, the treatment tool can be introduced from the forceps port 58.

A suction tube 100 is connected to the valve 98, and a suction button 34is attached to the valve 98. In a state in which the suction button 34is projected, the suction tube 100 communicates with the outside air.When the suction button 34 is pressed, the suction tube 100 is connectedto the forceps tube 96.

The suction tube 100 extends up to a suction connector 102 of the LGconnector 18. When the tube 28 (see FIG. 1) is connected to the suctionconnector 102, the suction tube 100 communicates with an unillustratedsuction apparatus. Thus, when the suction button 34 is pressed in astate in which the suction apparatus is driven, a lesion part, or thelike can be sucked through the forceps port 58.

In addition, one end of the manual insufflation tube 65 is detachablyconnected to the water storage tank 27 and communicates above the liquidsurface of the water storage tank 27. The other end of the manualinsufflation tube 65 is connected to a manual insufflation connector 145of the insufflation apparatus 66. Thus, carbon dioxide is supplied fromthe manual insufflation connector 145 of the insufflation apparatus 66to the water storage tank 27 through the manual insufflation tube 65. Inthe same manner as when air is supplied from the air pump 21 of thelight source apparatus 20 to the air supply tube 88, water or carbondioxide is jetted from the air/water insufflation nozzle 56 according tothe operation of the air/water insufflation button 32 by the operator.Note that the manual insufflation tube 65 corresponds to the secondexternal conduit.

Note that it is preferable that a control device (unillustrated) foralternatively controlling these drive operations is provided to preventsimultaneous supply of carbon dioxide from the insufflation apparatus 66and air from the air pump 21 to the air supply tube 88. For example, thecontrol device is provided in the light source apparatus 20, theinsufflation apparatus 66, or the processor 30 and performs control sothat the carbon dioxide supplied from the insufflation apparatus 66takes priority over the air supplied from the air pump 21. In this case,the air pump 21 is used as a spare gas supply source when a carbondioxide cylinder 110 is exhausted.

As described above, “manual insufflation” in the present description isdefined as insufflating carbon dioxide into the gastrointestinal tractfrom the insufflation apparatus 66 in response to manual operation by anoperator who manually operates a predetermined manual operation membersuch as the air/water insufflation button 32 of the endoscope 10.

Meanwhile, one end of the automatic insufflation tube 64 is detachablyconnected to the gas supply port 76 provided in the grip portion 74 ofthe insertion assisting tool 70, and the other end of the automaticinsufflation tube 64 is connected to an automatic insufflation connector144 of the insufflation apparatus 66.

The gas supply port 76 provided in the grip portion 74 of the insertionassisting tool 70 communicates with the insertion channel 68 inside theinsertion assisting tool 70 through a conduit 77 formed in the gripportion 74. In a state in which the insertion portion 12 is insertedinto the insertion channel 68, a gap is formed between the innerperipheral surface of the insertion assisting tool 70 and the outerperipheral surface of the insertion portion 12, and the gap forms adistal end opening portion 68 a at the distal end of the insertionassisting tool 70. Thus, the gas supply port 76 communicates with thedistal end opening portion 68 a through the conduit 77 and the insertionchannel 68 (gap).

Thus, the carbon dioxide is supplied from the automatic insufflationconnector 144 of the insufflation apparatus 66 to the insertion channel68 through the automatic insufflation tube 64 and the conduit 77, andthen introduced from the distal end opening portion 68 a of theinsertion channel 68 into the gastrointestinal tract.

Note that although not illustrated, a valve member as an airtightholding device which holds airtightness in close contact with an outerperiphery of the insertion portion 12 of the endoscope 10 is providednear an opening of the insertion channel 68 on the proximal end side ofthe grip portion 74 of the insertion assisting tool 70 to prevent thecarbon dioxide insufflated into the gastrointestinal tract from flowingout of the body through the insertion channel 68. Thus, the carbondioxide supplied from the insufflation apparatus 66 to the insertionchannel 68 of the insertion assisting tool 70 is insufflated from thedistal end opening portion 68 a into the gastrointestinal tract withoutflowing out of the body through the insertion channel 68.

As described above, “automatic insufflation” in the present descriptionis defined as automatically insufflating carbon dioxide from theinsufflation apparatus 66 into the gastrointestinal tract withoutoperator's manually operation of a predetermined manual operationmember.

Now, the description focuses on the configuration of the insufflationapparatus 66.

FIG. 4 is a block diagram illustrating the configuration of theinsufflation apparatus 66.

As described below, the insufflation apparatus 66 has a function toinsufflate carbon dioxide for manual insufflation from the manualinsufflation connector 145 through an internal insufflation conduit. Asillustrated in FIGS. 1 and 3, when the manual insufflation connector 145is connected to the water storage tank 27 through the manualinsufflation tube 65, the insufflation conduit is connected to the waterstorage tank 27 and the endoscope 10 and then to an insufflation conduitthrough which carbon dioxide is insufflated into the gastrointestinaltract. Thus, the insufflation system of the present embodiment includesthe insufflation conduit (second insufflation conduit) for manualinsufflation through which carbon dioxide is insufflated into thegastrointestinal tract according to a manual operation of the air/waterinsufflation button 32 of the endoscope 10.

As described below, the insufflation apparatus 66 also has a function toinsufflate carbon dioxide for automatic insufflation from the automaticinsufflation connector 144 through an internal insufflation conduit. Asillustrated in FIGS. 1 and 3, when the automatic insufflation connector144 is connected to the insertion assisting tool 70 through theautomatic insufflation tube 64, the insufflation conduit is connected tothe insertion assisting tool 70 and then to an insufflation conduitthrough which carbon dioxide is insufflated into the gastrointestinaltract. Thus, the insufflation system of the present embodiment includesthe insufflation conduit (first insufflation conduit) for automaticinsufflation through which carbon dioxide is automatically insufflatedinto the gastrointestinal tract.

As illustrated in FIG. 4, the insufflation apparatus 66 includes adecompression mechanism 114, a first solenoid valve 120, a secondsolenoid valve 122, first to fourth pressure sensors 126, 127, 128, and129, a control unit 130, and a front panel (operation panel) 131.

One end of a high-pressure hose 112 is detachably connected to a highpressure connector 113 of the insufflation apparatus 66, and the otherend thereof is connected to a carbon dioxide cylinder 110 as a gassupply source. In other words, the insufflation apparatus 66communicates with the carbon dioxide cylinder 110 through thehigh-pressure hose 112. Thus, carbon dioxide is supplied from the carbondioxide cylinder 110 to the insufflation apparatus 66 through thehigh-pressure hose 112 and the high pressure connector 113. Note thatthe gas supply source which supplies carbon dioxide to the insufflationapparatus 66 may be other than the carbon dioxide cylinder 110.

The high pressure connector 113 is connected to one end of an internalconduit 142 provided inside the insufflation apparatus 66. The internalconduit 142 is connected to a decompression mechanism 114 fordecompressing the carbon dioxide supplied from the carbon dioxidecylinder 110 to a predetermined pressure. An exit side of thedecompression mechanism 114 (side opposite to the high pressureconnector 113) is branched into two conduits 142 a and 142 b(hereinafter referred to as a first branch conduit 142 a and a secondbranch conduit 142 b).

The decompression mechanism 114 is a decompression device whichgradually reduces the pressure of the carbon dioxide supplied from thecarbon dioxide cylinder 110, to a proper pressure. The decompressionmechanism 114 includes two regulators (decompression valves) 116 and 118which are arranged in series. For example, the first regulator 116reduces the pressure of the carbon dioxide supplied from the carbondioxide cylinder 110, from 10 MPa to 0.6 MPa. Then, the second regulator118 reduces the pressure of the carbon dioxide reduced by the firstregulator 116, from 0.6 MPa to 0.05 MPa.

The first pressure sensor 126 is a pressure detecting device whichdetects the pressure of the carbon dioxide supplied from the carbondioxide cylinder 110. The first pressure sensor 126 is connected to theinternal conduit 142 between the high pressure connector 113 and thedecompression mechanism 114. The detection result of the first pressuresensor 126 is outputted to the control unit 130.

The second pressure sensor 127 is a pressure detecting device whichdetects the pressure of the carbon dioxide reduced by the decompressionmechanism 114. The second pressure sensor 127 is connected to theinternal conduit 142 between the decompression mechanism 114 and thefirst solenoid valve 120. The detection result of the second pressuresensor 127 is outputted to the control unit 130.

The first solenoid valve 120 is an opening and closing device which cancommunicate with and interrupt the internal conduit 142. The firstsolenoid valve 120 is disposed closer to a downstream side than thedecompression mechanism 114 in the internal conduit 142 and closer to anupstream side than a branch portion at which the internal conduit 142 isbranched into the branch conduits 142 a and 142 b. The first solenoidvalve 120 is opened or closed based on a control signal outputted fromthe control unit 130. The opening or closing of the first solenoid valve120 causes the internal conduit 142 to be communicated or interrupted,which collectively supplies or does not supply the carbon dioxide toeach of the branch conduits 142 a and 142 b.

Note that an open state of the first solenoid valve 120 is defined as astate in which the first solenoid valve 120 causes the conduit to becommunicated and a closed state thereof is defined as a state in whichthe first solenoid valve 120 causes the conduit to be interrupted. Notealso that the open state and the closed state of the second solenoidvalve 122 are defined in the same manner as above.

The first branch conduit 142 a constitutes part of the insufflationconduit (first insufflation conduit) for automatic insufflation, and oneend of the first branch conduit 142 a is connected to the automaticinsufflation connector 144. The second solenoid valve 122 is disposed onan upstream side of the first branch conduit 142 a (a branch portionside of the internal conduit 142).

The second solenoid valve 122 is an opening and closing device which cancommunicate with and interrupt the first branch conduit 142 a. Thesecond solenoid valve 122 is opened or closed based on a control signaloutputted from the control unit 130, switching to an open state ofcommunicating with the first branch conduit 142 a and a closed state ofinterrupting the first branch conduit 142 a.

The first branch conduit 142 a includes a first orifice 146 (throttleportion) as a first flow rate restricting device which is disposedcloser to a downstream side than the second solenoid valve 122. Thefirst orifice 146 has a smaller effective opening area of the conduitthan that on the upstream side and the downstream side of the firstorifice 146, thereby restricting the flow rate of carbon dioxide flowingin the first branch conduit 142 a, that is, the insufflation flow rateof carbon dioxide in the automatic insufflation.

Note that the effective opening area of the conduit refers to an area ofthe cross section perpendicular to the axis of the conduit. When theconduit has a circular cross section, the effective opening area of theconduit is found by multiplying the circumference ratio (pi) times theradius squared.

The third pressure sensor 128 and the fourth pressure sensor 129 arepressure detecting devices which detect a pressure inside thegastrointestinal tract through the insufflation conduit (the firstbranch conduit 142 a, the automatic insufflation tube 64, and theinsertion assisting tool 70) for insufflating carbon dioxide into thegastrointestinal tract. The third pressure sensor 128 and the fourthpressure sensor 129 are disposed closer to a downstream side than thefirst orifice 146 in the first branch conduit 142 a. The detectionresult of each of the pressure sensors 128 and 129 is outputted to thecontrol unit 130.

The present embodiment uses any one of the third pressure sensor 128 andthe fourth pressure sensor 129 as a main sensor and the other as a sparesensor. Thus, even if the main sensor fails, the spare sensor can beused instead to detect a pressure inside the gastrointestinal tract,thereby improving the reliability of pressure detection inside thegastrointestinal tract.

Note that if the difference between the pressure detected by the thirdpressure sensor 128 and the pressure detected by the fourth pressuresensor 129 exceeds a predetermined value, it can be judged that any oneof the pressure sensors fails. In addition, as the third pressure sensor128 and the fourth pressure sensor 129, pressure sensors having at leastone different characteristic in pressure measurement range, withstandingpressure, and resolution may be used to prevent the two pressure sensorsfrom failing at the same time. Further, such pressure sensors havingdifferent characteristics may be used to achieve both higher resolutionand wider pressure measurement range than by using only each pressuresensor for pressure detection.

The second branch conduit 142 b constitutes part of the insufflationconduit (second insufflation conduit) for manual insufflation, and oneend of the second branch conduit 142 b is connected to the manualinsufflation connector 145. The second branch conduit 142 b includes asecond orifice 148 (throttle portion) as the second flow raterestricting device. The second orifice 148 has a smaller effectiveopening area of the conduit than that on the upstream side and thedownstream side of the second branch conduit 142 b, thereby restrictingthe flow rate of carbon dioxide flowing in the second branch conduit 142b, that is, the insufflation flow rate of carbon dioxide in the manualinsufflation. Note that the effective opening area of the first orifice146 and the second orifice 148 as the first and second flow raterestricting devices may be fixed or variable. Note also that first andsecond flow rate restricting devices may restrict the insufflation flowrate by a device other than the orifice.

The front panel (operation panel) 131 is disposed in front of a housingconstituting the insufflation apparatus 66. The front panel 131 includesa power switch 132, a display portion 134, and an operation portion 136,each of which is connected to the control unit 130.

FIG. 5 is a diagram illustrating the front panel 131 of the insufflationapparatus 66. As illustrated in FIG. 5, the display portion 134includes: a remaining amount display portion 202 which displays theremaining amount of carbon dioxide of the carbon dioxide cylinder 110; agas warning display portion 204 which displays a warning when theremaining amount of carbon dioxide is less than or equal to apredetermined level; a set pressure display portion 206 which displays aset pressure inside the gastrointestinal tract; a pressure displayportion 208 which displays a pressure (current pressure) inside thegastrointestinal tract; and a pressure warning display portion 209 whichdisplays a warning when the pressure inside the gastrointestinal tractexceeds the set pressure.

The operation portion 136 includes: a pressure setting portion 210 forsetting a set pressure inside the gastrointestinal tract; and anautomatic insufflation button 212 for selecting ON (execution) or OFF(stop) of the automatic insufflation, and the like. When each portion ofthe operation portion 136 is operated, an operation signal correspondingto the operation is outputted to the control unit 130.

Now, by referring back to FIG. 4, the control unit 130 performs entirecontrol of the insufflation apparatus 66 and includes a CPU (CentralProcessing Unit), a memory, and the like, all of which are notillustrated. The memory stores control programs for operating theinsufflation apparatus 66 and various set information (such as a setpressure inside the gastrointestinal tract set by the pressure settingportion 210).

The control unit 130 displays the remaining amount of carbon dioxide ofthe carbon dioxide cylinder 110 on the remaining amount display portion202 based on the detection result of the first pressure sensor 126. Whenthe remaining amount of carbon dioxide is less than or equal to apredetermined level, the control unit 130 causes the gas warning displayportion 204 to display a warning and at the same time generates analarm. This makes it possible to replace the carbon dioxide cylinder 110with a new one before the carbon dioxide is exhausted.

In addition, the control unit 130 displays the pressure inside thegastrointestinal tract on the pressure display portion 208 based on thedetection result of the third pressure sensor 128 or the fourth pressuresensor 129 as the pressure detecting device, and at the same timedisplays the set pressure inside the gastrointestinal tract set by thepressure setting portion 210, on the set pressure display portion 206.

Further, the control unit 130 switches the setting between ON(execution) and OFF (stop) of the automatic insufflation according tothe pressing operation of the automatic insufflation button 212.

The automatic insufflation button 212 is linked with, for example, anautomatic return type switch. The control unit 130 detects whether ornot the automatic insufflation button is pressed down, according to anoperation signal which changes depending on the state of the switch.When it is detected that the automatic insufflation button is presseddown in a state in which the automatic insufflation is set to OFF, thecontrol unit 130 sets the automatic insufflation to ON until it isdetected that the automatic insufflation button is pressed down again.When it is detected that the automatic insufflation button is presseddown in a state in which the automatic insufflation is set to ON, thecontrol unit 130 sets the automatic insufflation to OFF until it isdetected that the automatic insufflation button is pressed down again.

Note that the device which sets the automatic insufflation to ON or OFFis not limited to the automatic insufflation button 212 like the presentembodiment.

When the automatic insufflation is set to ON, the control unit 130serves as a control device which controls the insufflation flow rate inthe automatic insufflation. More specifically, the control unit 130controls the opening and closing of the second solenoid valve 122 tosupply carbon dioxide from the automatic insufflation connector 144through the first branch conduit 142 a so that the pressure inside thegastrointestinal tract becomes the set pressure inside thegastrointestinal tract set by the pressure setting portion 210. Then,the carbon dioxide is insufflated into the gastrointestinal tractthrough the automatic insufflation tube 64 and the insertion assistingtool 70.

When the automatic insufflation is set to OFF, the control unit 130controls the second solenoid valve 122 to be in a closed state toprevent carbon dioxide from being supplied from the automaticinsufflation connector 144.

Meanwhile, it is set that carbon dioxide can be constantly supplied fromthe manual insufflation connector 145 through the second branch conduit142 b. The operator can operate the air/water insufflation button 32 ofthe endoscope 10 to insufflate carbon dioxide into the gastrointestinaltract through the water storage tank 27 and the endoscope 10, that is,the insufflation conduit for manual insufflation.

The insufflation system of the present embodiment configured as above isdisposed, for example, as illustrated in FIG. 6, in a state in which theinsertion portion 12 of the endoscope 10 is inserted into thegastrointestinal tract of the patient together with the insertionassisting tool 70 in a state of being inserted into the insertionchannel 68 of the insertion assisting tool 70. Then, carbon dioxide isinsufflated into the gastrointestinal tract from the insufflationapparatus 66 through the water storage tank 27 (unillustrated) and theendoscope 10 or the insertion assisting tool 70.

Note that the gastrointestinal tract into which the insertion portion 12of the endoscope 10 is inserted includes the esophagus, stomach, smallintestine (duodenum, jejunum, ileum), and large intestine (cecum, colon,rectum), and, particularly preferably the stomach, the large intestine,and the like. FIG. 6 illustrates a state in which the insertion portion12 of the endoscope 10 together with the insertion assisting tool 70 isinserted from the mouth of the patient into the stomach through theesophagus.

Now, the description focuses on an automatic insufflation mode togetherwith a manual insufflation mode of the insufflation system of thepresent embodiment.

In the manual insufflation mode, as illustrated in FIG. 7, when theoperator changes the vent of the air/water insufflation button 32 of theendoscope 10 from the open state (the state where the manualinsufflation operation is not performed) to the closed state (the statewhere the manual insufflation operation is being performed), carbondioxide is continuously insufflated into the gastrointestinal tract fromthe manual insufflation connector 145 through the second branch conduit142 b while the manual insufflation operation is in progress. When thevent of the air/water insufflation button 32 of the endoscope 10 isopened, the insufflation into the gastrointestinal tract is stopped.

As described above, the manual insufflation is performed by continuouslyinsufflating carbon dioxide. The insufflation flow rate (volume ofcarbon dioxide insufflated per unit time) during actual insufflation isa substantially constant insufflation flow rate MF (for example,liters/minute) determined by flow rate restriction by the second orifice148 of the second branch conduit 142 b in the insufflation apparatus 66.The effective opening area S2 of the second orifice 148 is set such thatthe insufflation flow rate MF is a value less than or equal to aninsufflation flow rate MFmax which is assumed not to burden the patient.

Meanwhile, as illustrated in FIG. 8, the automatic insufflation isperformed by intermittently (pulsewisely) insufflating carbon dioxide.

More specifically, when the operator operates the automatic insufflationbutton 212 of the insufflation apparatus 66 to switch the setting of theautomatic insufflation from OFF to ON, the second solenoid valve 122 isswitched every predetermined time between the open state and the closedstate while the automatic insufflation is set to ON. Then, carbondioxide is intermittently insufflated into the gastrointestinal tractfrom the automatic insufflation connector 144 through the first branchconduit 142 a. When the automatic insufflation is switched to OFF, thesecond solenoid valve 122 is switched to the closed state, which stopsinsufflation into the gastrointestinal tract.

Note that even in a state in which the automatic insufflation is set toON, if the pressure inside the gastrointestinal tract acquired by thepressure detecting device (the third pressure sensor 128 or the fourthpressure sensor 129) is greater than or equal to the set pressure set bythe pressure setting portion 210, the second solenoid valve 122 ismaintained in the closed state, which stops insufflation into thegastrointestinal tract. This does not mean stopping the automaticinsufflation itself, but when the pressure inside the gastrointestinaltract becomes less than the set pressure, intermittent insufflation intothe gastrointestinal tract is resumed.

Thus, in the automatic insufflation mode, as illustrated in FIG. 8, theintermittent insufflation is performed by alternately repeating aninsufflation step (step for one pulse) of actually continuouslyinsufflating carbon dioxide and a non-insufflation step (pressuredetection step) of continuously stopping (pausing) the insufflation.

Note that assuming that one cycle is defined as one repeating unitformed of one insufflation step and one non-insufflation step thatfollows that insufflation step, the period Ta of the cycle is set to apreset time. Then, based on the pressure inside the gastrointestinaltract, the ratio (t1/Ta: called duty ratio) of time t1 (time length) ofthe insufflation step per cycle is set or changed every cycle, and basedon the ratio, time t1 of the insufflation step and time t2 of thenon-insufflation step are set or changed.

Here, FIG. 9 illustrates three cycles with different duty ratio. Portion(B) in FIG. 9 illustrates a cycle with a maximum duty ratio in achangeable value range.

As illustrated in the figure, the insufflation flow rate in theinsufflation step of each cycle is a substantially constant insufflationflow rate A which is determined by flow rate restriction due to aneffective opening area S1 of the first orifice 146 of the first branchconduit 142 a.

Assuming that an average flow rate per cycle is defined as an averagevalue of the insufflation flow rate per cycle including one insufflationstep and one non-insufflation step following the one insufflation step,the average flow rate AF is calculated as follows.

AF=A×D, where D is duty ratio.

Here, the effective opening area S1 of the first orifice 146 is set soas to satisfy the condition where the average flow rate AF (average flowrate of the cycle illustrated in Portion (B) of FIG. 9) where the dutyratio D is a maximum value Dmax is less than or equal to theinsufflation flow rate MF in the manual insufflation (average flow rateAF≦insufflation flow rate MF). In order to satisfy this condition, theeffective opening area S1 of the first orifice 146 is set so as tosatisfy the following expression (1) relative to the effective openingarea S2 of the second orifice 148.

S1/S2=A/MF=AF/(Dmax×MF)≦1/Dmax  (1)

This satisfies the condition: average flow rate AF≦insufflation flowrate MF(≦MFmax) when the duty ratio D is any value of the changeablevalue range, and allows the automatic insufflation to be performed witha sense close to the manual insufflation. This also makes it possible toprevent the pressure inside the gastrointestinal tract from rapidlyincreasing and to achieve operability matched to a sense of theoperator.

Meanwhile, the duty ratio D is set based on a pressure difference ΔP(=Ps−P) between a pressure P inside the gastrointestinal tract acquiredby the pressure detecting device (the third pressure sensor 128 or thefourth pressure sensor 129) and a set pressure Ps set by the pressuresetting portion 210; and association data associating the pressuredifference ΔP with the duty ratio D. The association data is created inadvance and stored in a memory or the like of the control unit 130.

If the pressure difference ΔP is less than or equal to a predeteiiiiinedthreshold, the association data is associated such that the greater thepressure difference ΔP, the larger the duty ratio D (that is, the longerthe time t1 of the insufflation step). If the pressure difference ΔPexceeds the predetermined threshold, the association data is associatedsuch that the duty ratio D is a predetermined value regardless of thepressure difference ΔP (that is, the time t1 of the insufflation step isa constant time).

FIG. 10 is a graph illustrating a relationship between the pressuredifference ΔP and the time t1 of the insufflation step according to theassociation. As shown in FIG. 10, if the pressure difference ΔP is lessthan or equal to a threshold of 4.0 mmHg (about 533 Pa), the time t1 isset such that the greater the pressure difference ΔP, the longer thetime t1 of the insufflation step in one cycle. If the pressuredifference ΔP exceeds a threshold of 4.0 mmHg (about 533 Pa), the timet1 of the insufflation step in one cycle is set to 600 (ms).

Thus, the insufflation time per cycle in the automatic insufflation isset according to the pressure difference ΔP, and hence the automaticinsufflation into the gastrointestinal tract is stabilized. In addition,the average flow rate obtained when the insufflation time per cycle inthe automatic insufflation is set to a predetermined time is set to beless than or equal to the insufflation flow rate of the manualinsufflation, and hence the automatic insufflation into thegastrointestinal tract is performed with a sense close to the manualinsufflation. This makes it possible to prevent the pressure inside thegastrointestinal tract from rapidly increasing and to achieveoperability matched to the sense of the operator.

Note that when the pressure P inside the gastrointestinal tract isgreater than or equal to the set pressure Ps, insufflation is stopped inthe same manner as when the time t1 of the insufflation step is set to0. Therefore, it is equivalent to setting the duty ratio D to 0 when thepressure difference ΔP has a value less than or equal to 0 (0 andnegative values). However, in the present embodiment, the stopping ofthe insufflation in this case is not performed by setting a value of theduty ratio D, and hence the changeable values of the duty ratio D isassumed not to include 0. In addition, the pressure difference ΔP isonly assumed to be greater than 0.

Specifically, the duty ratio D is changed in the range from 0.1 to 0.7,and accordingly the time t1 of the insufflation step is changed in therange from Ta×0.1 to Ta×0.7.

For example, assuming that the period Ta of one cycle is 6/7 second, thetime t1 of the insufflation step is changed in the range from 0.6/7 to0.6 second.

At this time, the effective opening area S1 of the first orifice 146 ofthe first branch conduit 142 a is set with respect to the effectiveopening area S2 of the second orifice 148 of the second branch conduit142 b so as to satisfy the condition of being less than or equal to 1.43times (S1/S2≦1/0.7≈1.43) from the above expression (1).

Note that the time t2 of the non-insufflation step in the automaticinsufflation has a period of (6/7 minus 0.6) second even in the minimumtime (time assuming a maximum duty ratio D of 0.7). As illustrated inPortion (A) in FIG. 9, a predetermined time (wait time) t3, which is atime since immediately after the end of insufflation step within thetime t2 of the non-insufflation step, is a time of waiting for thepressure inside the gastrointestinal tract to be stabilized. In theremaining time (measurement time) t4, which is a time after the waittime t3 has elapsed, the pressure inside the gastrointestinal tract isdetected by the pressure detecting device (the third pressure sensor 128or the fourth pressure sensor 129).

Thus, in the automatic insufflation mode, insufflation is intermittentlyperformed and the pressure inside the gastrointestinal tract is detectedwhile the insufflation is stopped, and hence the automatic insufflationinto the gastrointestinal tract is stabilized.

Note that the wait time t3 may be any value as long as the time t3 isshorter than the time t2 of the non-insufflation step, at least, and maybe changed according to the time t2 of the non-insufflation step.

Now, the operation of the insufflation apparatus 66 of the presentembodiment will be described with reference to the flowchart in FIGS. 11and 12.

FIG. 11 is a flowchart illustrating an example of the operation of theinsufflation apparatus 66.

First, the power switch 132 of the insufflation apparatus 66 is turnedon, and then initial processing such as operation confirmation of eachportion is performed (Step S10).

Then, as pre-processing, the control unit 130 places the first solenoidvalve 120 in an open state so as to place the internal conduit 142 in acommunication state (Step S12). This enables manual insufflation ofcarbon dioxide into the gastrointestinal tract according to theoperation of the air/water insufflation button 32 of the endoscope 10.Subsequently, the manual insufflation is performed according to theoperation by the operator without the need for the control unit 130 toperform special processing until the control unit 130 switches the firstsolenoid valve 120 to a closed state, such as when the power switch 132is turned off.

Then, the control unit 130 acquires a pressure inside thegastrointestinal tract (Step S14). The detection of the pressure insidethe gastrointestinal tract is performed by the third pressure sensor 128or the fourth pressure sensor 129 as the pressure detecting device. Thedetection result is outputted to the control unit 130. The control unit130 calculates the actual pressure inside the gastrointestinal tract bycorrecting the pressure loss occurring from the pressure detectionposition to within the gastrointestinal tract. Thus acquired pressure ofthe gastrointestinal tract is displayed on the pressure display portion208.

Then, the control unit 130 determines whether or not the automaticinsufflation is set to ON (Step S16). As described above, based on theoperation of the automatic insufflation button 212, a determination ismade as to whether or not the automatic insufflation is set to ON. Notethat it is assumed that the automatic insufflation is set to OFF at thetime of the start of the insufflation apparatus 66, but the presentdisclosure is not limited to this.

Then, when the determination result is “NO” in Step S16, that is, whenit is determined that the automatic insufflation is not set to ON (theautomatic insufflation is set to OFF), the process moves to Step S18,where the control unit 130 places the second solenoid valve 122 in theclosed state so as to place the first branch conduit 142 a in anon-communication state. If the second solenoid valve 122 has been inthe closed state, the closed state is maintained. As a result, theautomatic insufflation into the gastrointestinal tract is turned off(stopped). Then, the process returns to Step S14 and repeats the processin and after Step S14.

Meanwhile, when the determination result is “YES” in Step S16, that is,when it is determined that the automatic insufflation is set to ON, theprocess moves to Step S20, where the control unit 130 performs automaticinsufflation control processing to be described below to turn on(execute) the automatic insufflation into the gastrointestinal tract.Then, the process returns to Step S14 and repeats the process in andafter Step S14.

Thus, the control unit 130 repeats the process in and after Step S14.When the power switch 132 is operated to set to OFF, the control unit130 places the first solenoid valve 120 in the closed state to stopoperation. Note that the power switch 132 is used to switch the firstsolenoid valve 120 between the open state and the closed state, but apredetermined operation member may be used for switching.

Now, the description focuses on the automatic insufflation controlprocessing.

While the automatic insufflation “ON” is selected, the determinationresult is “Yes” in Step S16 in FIG. 11, and then the processes in StepS14 and Step S20 are repeated. Then, the automatic insufflation controlprocessing like the flowchart of FIG. 12 is repeated. Note that FIG. 12omits the determination process in Step S16, and the process of placingthe first solenoid valve 120 in the closed state to stop the operationof the insufflation apparatus 66 according to the power switch 132“OFF”, which are assumed to be appropriately performed.

First, the control unit 130 acquires the pressure inside thegastrointestinal tract (Step S14). Then, the control unit 130 comparesthe acquired pressure P inside the gastrointestinal tract with the setpressure Ps preset by the pressure setting portion 210 to determinewhether or not the pressure P inside the gastrointestinal tract isgreater than or equal to the set pressure Ps (Step S30).

Then, when the determination result is “YES” in Step S30, that is, whenit is determined that the pressure P inside the gastrointestinal tractis greater than or equal to the set pressure Ps, the control unit 130returns to Step S14 without performing the following process, andrepeats the process in Step S14. Note that at this time, the secondsolenoid valve 122 is maintained in the closed state and theinsufflation into the gastrointestinal tract is stopped.

Meanwhile, when the determination result is “NO” in Step S30, that is,when it is determined that the pressure P inside the gastrointestinaltract is less than the set pressure Ps, the process moves to Step S32,where the control unit 130 calculates the pressure difference ΔP whichis a difference between the pressure P inside the gastrointestinal tractand the set pressure Ps (set pressure Ps−pressure P inside thegastrointestinal tract) (Step S32).

Then, based on the pressure difference ΔP calculated in Step S32, thecontrol unit 130 sets the duty ratio D of the insufflation step in theautomatic insufflation using the association data stored in the memoryin advance as described above (Step S34).

Thus, if the pressure difference ΔP is less than or equal to apredetermined threshold, the duty ratio D is set such that the greaterthe pressure difference ΔP, the larger the duty ratio D of theinsufflation step. If the pressure difference ΔP exceeds thepredetermined threshold, the duty ratio D is set to a predeterminedvalue (maximum value Dmax) regardless of the pressure difference ΔP.

Then, the control unit 130 sets (calculates) the time (length) t1 of theinsufflation step and the time (length) t2 of the non-insufflation stepbased on the duty ratio D of the insufflation step set in Step S34 (StepS36). Specifically, the time t1 of the insufflation step is obtained bymultiplying the period Ta of one cycle with the duty ratio D of theinsufflation step, and the time t2 of the non-insufflation step isobtained by subtracting the time t1 of the insufflation step from theperiod Ta of one cycle.

Then, when the time t1 of the insufflation step set in Step S36 haselapsed since the second solenoid valve 122 is switched from the closedstate to the open state, the control unit 130 switches the secondsolenoid valve 122 to the closed state (Step S38). Thus, the controlunit 130 performs insufflation into the gastrointestinal tract while thesecond solenoid valve 122 is in the open state.

Then, the control unit 130 switches the second solenoid valve 122 to theclosed state in Step S38, and then waits until a predetermined wait timet3 has elapsed (Step S40). The pressure inside the gastrointestinaltract is stabilized during the wait time t3.

When the wait time t3 has elapsed in Step S40, the process returns toStep S14, where the control unit 130 acquires the pressure inside thegastrointestinal tract.

Then, before the elapsed time since the second solenoid valve 122 wasswitched to the closed state in Step S38 reaches the time t2 of thenon-insufflation step, the control unit 130 performs the processes fromStep S30 to Step S36. Except for when the determination result is “Yes”in Step S30, the control unit 130 sets the time t1 of the insufflationstep and the time t2 of the non-insufflation step based on the newlyacquired pressure inside the gastrointestinal tract.

Then, at the same time when the previously set time t2 of thenon-insufflation step has elapsed (time t2 has elapsed after the waittime t3 elapsed), the control unit 130 performs a process of theinsufflation step in Step S38 to insufflate into the gastrointestinaltract.

Thus, the pressure inside the gastrointestinal tract is maintained tothe set pressure Ps by repeating the automatic insufflation controlprocessing.

Thus, according to the present embodiment, the operator can perform themanual insufflation at any time by performing the manual insufflationoperation regardless of whether or not the automatic insufflation is setto ON. However, it may be configured so that the manual insufflationcannot be performed when the automatic insufflation is set to ON. Forexample, a third solenoid valve similar to the second solenoid valve 122is disposed at a position which is closer to the downstream side thanthe branch portion when the internal conduit 142 is branched into thebranch conduits 142 a and 142 b, and is on the upstream side of thesecond orifice 148 in the second branch conduit 142 b of theinsufflation apparatus 66 illustrated in FIG. 4. In the embodiment thusmodified, when the automatic insufflation is set to OFF, the controlunit 130 sets the third solenoid valve to the open state to enable themanual insufflation, and when the automatic insufflation is set to ON,the control unit 130 sets the third solenoid valve to the closed stateto disable the manual insufflation.

Alternatively, when the operator performs the manual insufflationoperation in the state in which the automatic insufflation is set to ON,the insufflation in the automatic insufflation may be stopped.

Alternatively, when the pressure inside the gastrointestinal tractexceeds a predetermined value greater than or equal to the set pressurePs by manual insufflation, the manual insufflation may be stopped.

The present embodiment has been described by taking an example of thecase in which carbon dioxide is applied as the gas insufflated into thegastrointestinal tract, but the gas insufflated into thegastrointestinal tract is not limited to the carbon dioxide, and forexample, another gas such as helium gas may be used.

Hereinbefore, the insufflation system according to the presentdisclosure has been described in detail, but the present disclosure isnot limited to the above embodiment and it should be understood thatvarious improvements and modifications can be made to the presentdisclosure without departing from the spirit and scope of the presentdisclosure. Hereinafter, some modifications will be described.

First Modification

FIG. 13 is a schematic diagram schematically illustrating a conduitconfiguration of an endoscope as a first modification. In FIG. 13, thesame reference numerals or characters are assigned to the members commonor similar to those in FIG. 3, and the description thereof is omitted.

According to the first modification as illustrated in FIG. 13, part ofthe insufflation conduit for insufflating carbon dioxide into thegastrointestinal tract by automatic insufflation includes an externaltube 160 which is an external instrument disposed along a longitudinaldirection of the insertion portion 12 of the endoscope 10. The externaltube 160 is fixed to an outer periphery of the insertion portion 12 ofthe endoscope 10 by a fixing device (unillustrated) such as a tape. Theproximal end side of the external tube 160 includes a gas supply port162, to which one end of the automatic insufflation tube 64 isdetachably connected. The gas supply port 162 communicates with a distalend opening portion 164 of the external tube 160 through a conduit(unillustrated) formed inside the external tube 160. Thus, carbondioxide is supplied from the insufflation apparatus 66 to the gas supplyport 162, passing through the conduit inside the external tube 160, andis insufflated from the distal end opening portion 164 into thegastrointestinal tract.

According to the first modification, the automatic insufflation can beperformed even in a gastrointestinal tract deep portion into which it isdifficult to insert the insertion assisting tool 70.

Second Modification

FIG. 14 is an entire configuration diagram illustrating a schematicconfiguration of an endoscope system as a second modification. FIG. 15is a conduit configuration diagram illustrating an internalconfiguration of the endoscope illustrated in FIG. 14. In FIGS. 14 and15, the same reference numerals or characters are assigned to themembers common or similar to those in FIGS. 1 and 3, and the descriptionthereof is omitted.

According to the second modification as illustrated in FIGS. 14 and 15,part of the insufflation conduit for insufflating carbon dioxide intothe gastrointestinal tract by automatic insufflation includes theforceps tube 96 of the endoscope 10.

One end of the automatic insufflation tube 64 is detachably connected tothe forceps insertion portion 40, and the other end of the automaticinsufflation tube 64 communicates with the automatic insufflationconnector 144 of the insufflation apparatus 66. Thus, carbon dioxide issupplied from the automatic insufflation connector 144 of theinsufflation apparatus 66 into the automatic insufflation tube 64,passing through the forceps insertion portion 40 and the forceps tube96, and is insufflated from the forceps port 58.

The second modification allows even the endoscope system without usingthe insertion assisting tool 70 to perform the automatic insufflationwithout the need to provide a special conduit.

Third Modification

FIG. 16 is a schematic diagram schematically illustrating a conduitconfiguration of an endoscope as a third modification. FIG. 17 is ablock diagram illustrating a configuration of an insufflation apparatusas a third modification. In FIGS. 16 and 17, the same reference numeralsor characters are assigned to the members common or similar to those inFIGS. 3 and 4, and the description thereof is omitted.

The third modification is the same as the first modification in that theexternal tube 160 externally provided along the longitudinal directionis configured in the insertion portion 12 of the endoscope 10 as part ofthe insufflation conduit, but is different from the first modificationin that a pressure detecting conduit for detecting the pressure insidethe gastrointestinal tract is configured separately from theinsufflation conduit.

Specifically, as illustrated in FIG. 16, one end of the pressuredetecting tube 166 is detachably connected to the forceps insertionportion 40 of the endoscope 10, and the other end of the pressuredetecting tube 166 is connected to the pressure detecting connector 168of the insufflation apparatus 66.

As illustrated in FIG. 17, inside the insufflation apparatus 66, aninternal conduit 170 is provided. The internal conduit 170 is in anon-communication state with respect to the internal conduit 142 and thebranch conduits 142 a and 142 b. One end of the internal conduit 170 isconnected to the pressure detecting connector 168. A fifth pressuresensor 172 is connected to the internal conduit 170. The fifth pressuresensor 172 detects a pressure inside the gastrointestinal tract througha pressure detecting conduit (the internal conduit 170, the pressuredetecting tube 166, and the forceps tube 96) configured separately fromthe insufflation conduit (the first branch conduit 142 a, the automaticinsufflation tube 64, and the external tube 160) for supplying carbondioxide into the gastrointestinal tract.

According to the third modification, when the pressure inside thegastrointestinal tract is detected, the pressure inside thegastrointestinal tract is detected through the pressure detectingconduit configured separately from the insufflation conduit forinsufflating carbon dioxide into the gastrointestinal tract. This makesit possible to detect the pressure inside the gastrointestinal tract ina stable manner and with high precision without being affected by theinsufflation into the gastrointestinal tract. This accordingly makes itpossible to set the pressure inside the gastrointestinal tract to atarget pressure in a simple manner and with high precision.

Note that the third modification is configured such that part of theinsufflation conduit includes the external tube 160, and part of thepressure detecting conduit includes the forceps tube 96, but withoutbeing limited to this. For example, the third modification may bereversely configured such that part of the insufflation conduit includesthe forceps tube 96, and part of the pressure detecting conduit includesthe external tube 160. In other words, one end of the automaticinsufflation tube 64 may be connected to the forceps insertion portion40, and one end of the pressure detecting tube 166 may be connected tothe gas supply port 162 of the external tube 160.

Alternatively, when a plurality of treatment tool channels (treatmenttool insertion channels) are provided in the insertion portion 12 of theendoscope 10, one treatment tool channel may be configured as part ofthe insufflation conduit, and the other treatment tool channel may beconfigured as part of the pressure detecting conduit.

Alternatively, like the embodiment in FIG. 1, when the insertionassisting tool 70 is used, the insertion channel 68 of the insertionassisting tool 70 may be configured as part of the insufflation conduit,and the forceps tube 96 which is an internal conduit of the endoscope 10may be configured as part of the pressure detecting conduit. Stillalternatively, this may be reversely configured.

What is claimed is:
 1. An insufflation system which insufflates a gassupplied from a gas supply source into a lumen of a living body, theinsufflation system comprising: a first insufflation conduit throughwhich the gas is automatically insufflated into the lumen; a secondinsufflation conduit through which the gas is insufflated into the lumenin response to manual operation; a pressure detecting device configuredto detect a pressure inside the lumen; and a control device configuredto control an insufflation flow rate of the gas insufflated through thefirst insufflation conduit, based on a pressure difference between thepressure detected by the pressure detecting device and a preset setpressure, the control device configured to alternately repeat aninsufflation step of insufflating the gas through the first insufflationconduit and a pressure detection step of stopping insufflating the gasand detecting the pressure inside the lumen by the pressure detectingdevice, wherein when one cycle is defined as one repeating unit formedof the insufflation step and the pressure detection step, an averageflow rate per cycle is set to be less than or equal to the insufflationflow rate when the gas is insufflated through the second insufflationconduit.
 2. The insufflation system according to claim 1, wherein whenthe pressure difference between the pressure detected by the pressuredetecting device and the set pressure is less than or equal to athreshold, the control device sets an insufflation time per cycle of thegas insufflated through the first insufflation conduit such that thegreater the pressure difference, the longer the insufflation time percycle, when the pressure difference exceeds the threshold, the controldevice sets the insufflation time per cycle of the gas insufflatedthrough the first insufflation conduit to a predetermined timeregardless of the pressure difference, and the average flow rate whenthe insufflation time per cycle is set to the predetermined time is setto be less than or equal to the insufflation flow rate when the gas isinsufflated through the second insufflation conduit.
 3. An insufflationsystem which insufflates a gas supplied from a gas supply source into alumen of a living body, the insufflation system comprising: a firstinsufflation conduit through which the gas is automatically insufflatedinto the lumen; a second insufflation conduit through which the gas isinsufflated into the lumen in response to manual operation; a pressuredetecting device configured to detect a pressure inside the lumen; acontrol device configured to control an insufflation flow rate of thegas insufflated through the first insufflation conduit, based on apressure difference between the pressure detected by the pressuredetecting device and a preset set pressure, the control deviceconfigured to alternately repeat an insufflation step of insufflatingthe gas through the first insufflation conduit and a pressure detectionstep of stopping insufflating the gas and detecting the pressure insidethe lumen by the pressure detecting device; a first flow raterestricting device configured to restrict the insufflation flow rate ofthe gas insufflated through the first insufflation conduit; and a secondflow rate restricting device configured to restrict the insufflationflow rate of the gas insufflated through the second insufflationconduit, wherein when one cycle is defined as one repeating unit formedof the insufflation step and the pressure detection step, a restrictedamount of the insufflation flow rate of the gas by the first flow raterestricting device and the second flow rate restricting device is setaccording to a duty ratio of an insufflation time per cycle of the gasinsufflated through the first insufflation conduit.
 4. The insufflationsystem according to claim 3, wherein the first flow rate restrictingdevice includes a first orifice, and the second flow rate restrictingdevice includes a second orifice, wherein when the duty ratio of theinsufflation time per cycle of the gas insufflated through the firstinsufflation conduit is less than or equal to D, a ratio of an effectiveopening area of the first orifice to an effective opening area of thesecond orifice is configured to be less than or equal to 1/D times. 5.The insufflation system according to claim 4, wherein the duty ratio ofthe insufflation time per cycle of the gas insufflated through the firstinsufflation conduit is configured to be less than or equal to 0.7, andthe effective opening area of the first orifice is configured to be lessthan or equal to 1.43 times the effective opening area of the secondorifice.
 6. An insufflation apparatus which insufflates a gas suppliedfrom a gas supply source into a lumen of a living body, the insufflationapparatus comprising: a pressure detecting device configured to detect apressure inside the lumen; and a control device configured to control aninsufflation flow rate of the gas supplied to a first external conduitwhich is connected to the insufflation apparatus and through which thegas is automatically insufflated into the lumen, based on a pressuredifference between the pressure detected by the pressure detectingdevice and a preset set pressure, the control device configured toalternately repeat an insufflation step of insufflating the gas into thefirst external conduit and a pressure detection step of stoppinginsufflating the gas and detecting the pressure inside the lumen by thepressure detecting device, wherein when one cycle is defined as onerepeating unit formed of the insufflation step and the pressuredetection step, an average flow rate per cycle of the gas supplied tothe first external conduit is set to be less than or equal to theinsufflation flow rate of the gas supplied to a second external conduitwhich is connected to the insufflation apparatus and through which thegas is insufflated into the lumen in response to manual operation.
 7. Aninsufflation apparatus which insufflates a gas supplied from a gassupply source into a lumen of a living body, the insufflation apparatuscomprising: a pressure detecting device configured to detect a pressureinside the lumen; a control device configured to control an insufflationflow rate of the gas supplied to a first external conduit which isconnected to the insufflation apparatus and through which the gas isautomatically insufflated into the lumen, based on a pressure differencebetween the pressure detected by the pressure detecting device and apreset set pressure, the control device configured to alternately repeatan insufflation step of insufflating the gas into the first externalconduit and a pressure detection step of stopping insufflating the gasand detecting the pressure inside the lumen by the pressure detectingdevice; a first flow rate restricting device configured to restrict theinsufflation flow rate of the gas supplied to the first externalconduit; and a second flow rate restricting device configured torestrict the insufflation flow rate of the gas supplied to a secondexternal conduit which is connected to the insufflation apparatus andthrough which the gas is insufflated into the lumen in response tomanual operation, wherein when one cycle is defined as one repeatingunit formed of the insufflation step and the pressure detection step, arestricted amount of the insufflation flow rate of the gas by the firstflow rate restricting device and the second flow rate restricting deviceis set according to a duty ratio of an insufflation time per cycle ofthe gas supplied to the first external conduit.